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By John D. Bardill

This report covers magnetic surveys in the Dannemora arca , which was part of a general survey of magnetite deposits in New York started in 1943 . The objective of these surveys was to afford a basis for the selection of exploration projects .

Jan 1, 1947

By Fred N. Kissell

Air recirculation caused by dust scrubbers at coal mine working faces was examined by the Federal Bureau of Mines with regard to the potential hazards caused by a possible buildup of methane gas. A theoretical analysis indicated that there was no apriori way to predict the effect of scrubber recirculation on methane concentration levels. Experiments conducted in a full-scale model of a working face area indicated that methane levels were dependent to a great extent on the location of the scrubber exhaust, but that the scrubber recirculation did not substantially increase the methane concentration above those levels that would have prevailed were the scrubber not in operation. An analysis of two underground scrubber trials showed that the scrubbers had no significant effect on methane levels, and a review of explosions attributed to recirculation showed that these were characterized by a lack of fresh air as well as recirculation. It was concluded that high methane levels are due more to a lack of fresh air than to recirculation.

Jan 1, 1975

By W. H. Ode, W. A. Selvig

Briefly, this swelling test consists in heating 1 gram of pulverized coal in a silica crucible over a gas flame under prescribed conditions to form a coke button which is compared in size and shape with a series of standard profiles numbered 1 to 9. These profiles are intended to cover the size and shape of buttons obtained from coals covering a wide range in plastic properties. The number of the standard profile with which the maximum cross-sectional area of the button most nearly corresponds is recorded as the swelling index. Although the swelling test showed poor relationships with the various tests that were used for measuring expansion or contraction of coal during carbonization, it gave indications of having value in measuring free-swelling and coking properties of coals when burned on fuel tests. An opportunity to investigate this occurred when an engineering company reported pronounced differences in burning characteristics on grates of various shipments of Pocahontas coal. Some of these coals gave trouble by swelling excessively and clogging the grate. Samples were obtained, and it was found that the troublesome coals gave radically higher free-swelling numbers than did the coals that performed satisfactorily. Also, it was found that the free-swelling index test gave better differentiation between coals than could be obtained from the coke buttons from the standard volatile-matter test or iron agglutination-value results. The results of the free-swelling test were confirmed by the Subcommittee on Plasticity and Swelling, Coal, a special group of the Subcommittee, under the chairmanship of R.A. Shuman, worked along with the test method. Estberg, Limacher, and Shuman of the Battelle Memorial Institute investigated the various factors affecting the test and found that the swelling index was a good indication of the suitability of coal for performance on residential-type stokers from the swelling characteristics of the coal. Data were presented that also showed that the index was helpful in the selection of coal for industrial underfeed stokers.

Feb 1, 1948

By A. W. Frolli

This paper, describing the mining and reduction methods and costs at the Oceanic quicksilver mine, is one of a series of similar reports being prepared by the Bureau of Mines on various mines in the United states. The property, which is owned and operated by the Anglo American Mining Corporation, Ltd., is 5 miles east of Cambria, San Luis Obispo County, Calif. It lies in a region of steep hills and sharply incised canyons on the west slope of the Santa Lucia Range at an elevation of about 500 feet above sea level. The climate is ideal for living and operating conditions. A 40-mile paved highway connects the mine with San Luis Obispo, the nearest convenient railroad town.

Jan 1, 1937

By D. H. Platt

Data obtained from on-the-site observations have been compiled to describe the equipment and installation methods used for satisfactory suspension roof support in a large-diameter tunnel. Experimental roof bolting was undertaken from June 1950 until May 8, 1951, in the East Delaware tunnel, which is part of the Delaware aqueduct in Delaware and Sullivan Counties, N. Y. Revised suspension-roof-support plans and specifications were prepared during the spring of 1951 by the City of New York Board of Water Supply; these were approved by the State of New York Department of Labor April 13, 1951, and adopted by the City of New York Board of Water Supply on May 8, 1951.

Jan 1, 1952

By Stephen A. Swan

Bureau of Mines research has not included analyses of mining dredge safety since 1948. Because of the increasing use of dredges, 63 fatal accidents and several hundred nonfatal injury accidents involving dredges were examined. Also, 31 working dredges and 3 dredge manufacturers were visited to acquire qualitative information. Drowning accidents represented 59 pct of the fatalities and are delineated in detail. Also, countermeasures against other hazards are discussed.

Jan 1, 1985

By E. D. Gradner

During 1924 a number of lives were lost and other men incapacitated by the toxic effects of gases produced in blasting in massive sulphides. In one mine, three men working in a raise were caught by gases from blasting a drift round in massive sulphide on the level. The round in the drift was shot ahead of time and it was necessary for the three men to travel through the gases to the intake air course. Two of the men lost their lives, and the third was injured, apparently for life. Other men at this same mine have been caught in the gases at blasting time and seriously injured. At a second mine, the gases from blasting in sulphides appear to be very dangerous, and it was necessary to send a number of men who were caught in such gases to the hospital. One man who was seriously gassed has not recovered in over a year is time. Another man similarly gassed soon died of influenza.

Jan 1, 1926

By David C. Minton

This paper describes in detail the cost of equipping and developing the Golden Belt mine, Yavapai County, Ariz. These costs should be typical of the average small gold mine in central Arizona which has been equipped with used machinery a, a minimum of capital expenditure. The conditions of remoteness, transportation, water, and power supply are about average for properties in the Bradshaw fountains and that vicinity. There are several mines in the district in the process of development and several dormant properties that might be opened in the future. The Golden Belt group of claims was taken over by the present management in May, 1931. Although some active development has been carried on in recent years, resumption of work at the old property required entire rehabilitation of the equipment and camp. As the water level had not been reached, there was no problem of dewatering. In the presentation of costs in this paper an evaluation of the cost of equipment and development work as taken over by the Golden Belt Mines, Inc., has been made. Enact data, however, on previous exploration and construction costs are lacking. The total cost of equipping and developing the mine to its present stage has been obtained by adding the disbursements of the present management to the above-mentioned evaluation. These costs do not include the cost of replacing camp, equipment destroyed by fires, of unsuccessful milling experiments, management, or obsolete equipment on the property.

Jan 1, 1933

By I. L. Nichols

Volatilization of cesium from pollucite ore was investigated as an initial step in the production of purified cesium metal or cesium salts. High recovery of cesium and rubidium as chloride sublimates was accomplished by 2-hour roasts in a tube furnace using charges containing 1 part ore, 2 parts limestone, and 0.23 part calcium chloride. Recoveries of cesium in the sublimate product were 89.1, 92.9, and 95.2 pct, respectively, using 1,100° C and vacuum, 1,250° C with an air sweep, and 1,250° C without an air sweep. Most of the lithium, sodium, and potassium sublimed with the cesium and rubidium, but virtually none of the calcium, aluminum, and silicon in the charges was volatilized.

Jan 1, 1966

By Allan M. Johnson

Case histories were used to document and evaluate deficiencies in underground mine closures which have resulted in post-operation problems such as subsidence shaft failures, acid or toxic water drainage and others. Three different underground mining districts in the United States were investigated; 1) an iron mining district in Michigan 2) coal mining districts in eastern Ohio and southern Illinois and 3) three metal mining districts in central Colorado. Previous work in the Michigan district on problems with subsidence and acid water drainage provided the background from which the concept for this project was developed Student investigators working towards their MS degrees in Mining Engineering did the work on the eastern coal and western metal districts. The combined studies show that problems from acid water drainage, subsidence and inadequately protected mine shafts are the most severe and widespread. Suggestions of a technical nature are presented as partial solutions to some of these problems. It was determined that pre-closure evaluations could result in the identification of some potential problems that may occur after the mine is closed. Early recognition of these problems would be an advantage for at this time more options are available to the mine operator to either prevent them or to plan for their occurrence. Mine closure and reclamation should be considered as a part of mining and be incorporated in the mining plan. This would result in reduced environmental impact and would be achieved at a lower overall cost to the mining companies and to society. The role of water in the occurrence of several types of subsidence during mine flooding was significant at some mines in the Michigan district. These mechanisms which involve, friction reduction, gravity loading, overburden transport and hydraulic forces in a flooded mine probably have a broader effect than is currently recognized. Control of these processes may offer some interesting options during mine closure. It is recognized that technical solutions alone cannot provide all of the answers to problems associated with underground mines. Education, modified attitudes on the part of regulators and operators, and a more realistic perception of the importance and value of mining by the general public are also needed.

Jan 1, 1983

By C. C. Popoff

The development of glass-making industries in the Pacific Northwest as well as other industries that use pure silica has been retarded by lack of local supplies of low-cost raw material. Several quartz deposits along the Skagit River constitute the only known source of relatively pure silica within the range of cheap transportation to the Seattle industrial area. Although some silica has been mined from these deposits, very little information regarding their size, grade, and other physical characteristics has been available to the general public. As a part of its program of investigation of the mineral resources of the Pacific Northwest, the Bureau of Mines assigned the writer to examine the Skagit River silica deposits in October 1946. This report presents the factual data obtained from an examination of the so-called Stoner, Bacon Creek, and Pressentin deposits. These deposits are the largest and most easily accessible known to exist in the area. The deposits are near Marblemount, which is on State Highway 17A. They are within 1 mile to 1-1/2 miles of the Skagit. River Railway, which provides transportation to Seattle, a distance of 130 miles. None of the deposits has been developed thoroughly. The Stoner deposit, however, has been developed by a quarry about, 5,0 feet square and has been exposed by hydraulic removal of the overburden throughout a distance of 180 feet along the hanging wall of the vein

Jan 1, 1949

By Edward W. Parsons

Conventional rock-bolt anchors often fail when installed in weak formations. The purpose of this work was to develop an anchor that would utilize an explosive charge to secure anchorage in any type of rock. Laboratory work to develop a rock-bolt anchored by explosive forming was initiated using rock-bolt models which had a drilled explosive chamber and were composed of various metals. This was followed by the use of several types of seamless tubing which were expanded with a water-coupled explosive capsule. By attaching a length of solid bolt to the anchor tube, a prototype explosive-anchored rock bolt was made. More than 150 laboratory models were expanded during this phase of development, During two field tests in underground mines (A and B) and one in an open- cut mine (C), 87 explosive-anchored bolts, 9 slot-and-wedge bolts, 2 bolts anchored with expanding grout, and 28 expansion-shell bolts consisting of three types of shells were installed and subjected to pull tests. The field tests were run to determine the effects of variables such as the amount and placement of the explosive charge, design changes in the bolt, and the effect on anchorage of different pull-test techniques. The field tests revealed the following: Mine A. The explosive-anchored rock bolt was feasible, but changes were necessary in bolt materials and in some details of bolt design. Mine B. The design and materials of the bolt gave excellent results in hard fractured rock, but no information was obtained concerning variations in the dimensions of the anchor unit or in the explosive charge. Nine C. Varying the explosive charge to produce a beaded surface on the bolt tube and tightening of the anchored bolt before pull-testing were found to increase significantly the anchorage obtained in soft ground.

Jan 1, 1963

By W. E. Young, D. T. Delicate

This study was made to present the mining methods and costs of a uranium mine typical of other mines in the highly productive Westwater Canyon member of the Morrison formation in New Mexico. Four mining methods have been used at the Section 23 mine: the retreat- room-and-pillar method, a sublevel-slicing method (also called top-slicing), the horizontal-cut-and-fill method, and a modification of the ring-drill method. The application of the methods at this mine and at other mines in the area should be of benefit to operators with similar problems. Ore bodies in the Section 23 mine are irregularly shaped and vary in size, in rock strength, in moisture content, and in uranium concentrations; different mining methods are required and mining costs are not constant. A 6-month period of operation at the Section 23 mine was analyzed and mining costs, not including amortization, depreciation, or Federal taxes, averaged about $6.80 per ton.

Nov 1, 1963

By J. B. Ligon

Blast induced stress waves, propagating along the surface of a drift of an underground hardrock mine, were recorded and analyzed. Resistance strain gages, accelerometers and a velocity pickup were used in making the measurements. Although a full face blast was recorded, the stress waves were initiated by single borehole blasts for the majority of the project. A special instrument trailer was designed, constructed and utilized during the project. A reliable strain wave transducer was developed for measuring the stress waves propagating on the drift surface. A correlation study between strain and acceleration signals for P-waves was made which agreed well with theory. The use of stemming was found to reduce strain and acceleration magnitudes as predicted.

Jan 1, 2011

By R. E. Lindstrom, D. J. Bauer

Studies were conducted to assess the potential of naphthenic acid as a fractional extractant for rare- earth mixtures and yttrium in sulfate solution . Naphthenic acid was an effective extractant , and separation factors were favorable in the presence of aqueous phase chelating agents . Addition of EDTA to the naphthenic acid extraction system resulted in average separation factors of 2.2 between adjacent yttrium- group elements , whereas DTPA resulted in average separation factors of 3.5 between adjacent cerium- group elements . EDTA was of value in separating yttrium from the rare- earth elements . Thorium and uranium were preferentially extracted over the trivalent rare- earth elements by naphthenic acid .

Jan 1, 1964

By Forest J. Sur

"This report describes an exploratory project conducted by the Bureau of Mines on a fluorite deposit near Vado, N. Mex. Results of trenching are given. Together with analyses made upon samples of the ore. The Federal Geological Survey3/ completed a preliminary geologic study and mapped the deposit during the summer of 1944. A Bureau engineer examined the deposit in August 1944. As a result of these investigations, it was concluded that the deposit contained substantial inferred ore reserves. Exploratory work was recommended to obtain information that might possibly lead to production from the property. Assistance was given the Bureau by the Geological Survey.A gasoline-powered air compressor, other equipment, and supplies were delivered to the property from January 20 to 25, 1943. Trenching began under the direction of a Bureau of Mines engineer on January 25, 1947, and ended on March 15, 1945. The results of trenching and sampling form he basis of this report.In its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. IT is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, R.G. Knickerbocker, chief, analyzes samples and performs beneficiation tests. Both these branches are under the supervisions of Dr. R. S. Dean, assistant director."

Sep 1, 1946

By Raymond Derzay

This publication is intended to be of value to the mineral industry in establishing and maintaining effective programs for preventing noise-induced hearing loss. Factors involved in this loss and the need for and the requirements of an effective hearing conservation program are discussed. The legal and legislative history of compensation for hearing loss is briefly reviewed. A review of statutes is not attempted since several States have recently modified) or are in the process of modifying their laws regarding permissible noise exposures) required hearing protection) and/or compensation for hearing loss. A review of other aspects of the problem of industrial noise in terms of medical, physiological) and psychological frames of reference is included. A hearing conservation program is described in detail. Appendixes detailing the names and addresses of a few equipment suppliers are included. References are provided for those who may wish to delve more deeply into the medical, technical, and scientific considerations of noise and its effect on man.

Jan 1, 1972

By Paul C. Turner

The U.S. Bureau of Mines, through an Interagency Agreement with the U.S. Army Tank-Automotive Command (TACOM), has successfully developed a steel expendable pattern casting process (EPC) for the manufacture of armorplate. The new armor is lighter and more ballistically effective than conventional rolled homogeneous armor (RHA), and costs less. An applique armor spinoff from the program was field-tested during the Gulf War. The applique armor withstood direct impacts from enemy munitions without failure.

Jan 1, 2010

By J. W. Eckerd, W. S. Sanner, P. L. Woolf, R. E. McKeever

The Bureau of Mines experimental blast furnace was operated successfully with anthracite metallurgical briquets . Tuyère pressures were higher and more erratic than for operations using coke , and furnace " hangs " occurred more frequently . Higher hot - blast temperatures were required to maintain the quality of the metal . By using higher hot blast temperatures , the fuel and production rates and slag volumes were comparable to those obtained for all - coke operation . The anthracite metallurgical briquets exhibited excellent mechanical strength and descended through the shaft of the furnace with little breakage or reduction in size .

Jan 1, 1964

By J. D. Kalasky, Stephen Krickovic

A degasification experiment was conducted in a Pocahontas No. 3 coalbed mine in Virginia. It involved (1) drilling holes in the coalbed in the out- side headings of a set of five being developed in virgin area, and (2) conducting a methane emission rate study as mining progressed and additional holes were drilled. Degasification from all drill holes except the longest in each of the outside headings and the first three drilled (excluding the in-situ pressure hole), was erratic and inconsequential in methane emission rates. The two longest holes liberated 66 and 79 cfm of methane, which is significant for the coalbed, but such quantity lasted a relatively short time; the first three were uniform but low in methane emission.

Jan 1, 1972